device for connecting to a liquid source

ABSTRACT

A connecting device comprises a buffer chamber ( 2 ), a first connecting line ( 3 ) between a liquid source ( 4 ) and an inlet ( 5 ) of the buffer chamber, a second connecting line ( 9 ) between an outlet ( 10 ) of the buffer chamber and the medical treatment apparatus ( 11 ), two valves ( 7, 8 ) arranged in series on the first connecting line, a pump ( 12 ) on the second connecting line, two liquid level sensors ( 15, 16 ) operating in the buffer chamber, a vent valve ( 18 ) connected to the buffer chamber. The liquid source is a centralised distribution plant of dialysate, while the medical treatment apparatus is a dialysis apparatus. The invention prevents back-contamination of the centralised plant with disinfectant sourced from the dialysis apparatus.

BACKGROUND OF THE INVENTION

The present invention relates to a connecting device to a source of aliquid.

Specifically, though not exclusively, the invention can be usefullyapplied in connecting a medical apparatus, for example a dialysisapparatus, to a centralised supply plant of a medical liquid, forexample a dialysis liquid.

As known, a centralised supply plant of liquid for dialysis is connectedto a plurality of remote dialysis stations by means of a distributioncircuit. One of the problems connected to this type of plant isprotection against the risk of back-contamination of the wholedistribution circuit due to a malfunctioning of a dialysis station inwhich, for example, a chemical disinfection process is under way: inthis case, the propagation of the disinfectant in the distributioncircuit would represent an enormous risk for the safety of the patientssubject to treatment in the other dialysis stations.

US Patent Publication No. US 2005/0047959 describes a connecting devicefor connecting a medical apparatus (for example a dialysis machine or ainverse osmosis system) with a supply system of a cleaning ordisinfecting agent. The connecting device comprises a buffer chamber orstorage chamber, a connection line connecting the upper part of thebuffer chamber with the medical apparatus, a siphon connecting the lowerpart of the buffer chamber with a source of the cleaning or disinfectingagent, and a vent line which connects the upper part of the bufferchamber with the external environment. The connecting line is providedwith a pump for moving the cleaning or disinfecting agent and a closurevalve. The buffer chamber is provided with a liquid sensor arranged at alevel which is lower with respect to the top of the siphon and issuperior with respect to the mouth of the siphon in the buffer chamber.The vent line is provided with a vent valve. During the washing anddisinfecting procedure of the medical apparatus the closure valve isopened, the pump activated, while the vent valve is closed. During theother phases of the medical apparatus the closure valve is closed, thepump still, and the vent valve is open. The siphon ensures that at theend of the washing and disinfecting procedure, the buffer chamber isemptied of liquid. Further, the connecting device provides a securitysystem which is able to detect if, beyond the procedure of washing anddisinfecting, there are liquid leaks passing from the medical apparatusto the buffer chamber through the closure valve. The device serves toreduce the risk of contaminating the medical apparatus with the washingand disinfecting liquid when not in the stage of washing anddisinfecting (for example during a medical treatment of a patient), aswell as the risk of altering the washing and disinfecting liquid in acontrolled way with medical fluid coming from the medical apparatus. Inthis way it is possible to keep the washing and disinfecting liquidconstantly connected to the medical apparatus.

U.S. Pat. No. 5,015,389 describes a system for distribution ofbicarbonate concentrate to a plurality of remote hemodialysis units, inwhich the bicarbonate concentrate is kept in continuous re-circulationalong a ring-shaped distribution line, even in the presence ofvariations in the flow demand for the concentrate by the varioushemodialysis units.

FR 2704150 discloses a plurality of dialysis machines connected to acentral water purification unit by means of a supply ring which startsfrom the above-mentioned central unit and returns to the same unit. Eachdialysis machine is provided with a connector for connecting theabove-mentioned supply ring in order to ensure a continuous circulationof water along the ring and the taking of the necessary delivery ofwater for the functioning of the dialysis machine. Each connector isconfigured for connecting to a respective counter-connector which ispredisposed along the supply ring. Each counter-connector is normallyclosed and is opened by effect of the mechanical interaction with aprojection on the connector, predisposed on the dialysis machine. Eachconnector is provided with a solenoid to enable the water supplied tothe supply ring to enter the dialysis circuit of the single dialysismachine.

DE 10047849 C1 describes a pure water distribution system, the waterbeing prepared by an inverse osmosis plant, in which a ring-closedcircuit supplies pure water to a plurality of dialysis machines. Thesame ring-closed circuit can be used to distribute the cleaning liquidto the various dialysis machines during the non-treatment stage (servicestage) of the machines, in general during the night-time. Each dialysismachine is provided with a valve enabling ingress of the cleaning liquidcoming from the distribution circuit. Further, the distribution circuitis provided with one or more temperature sensors connected to thecontrol unit of each dialysis machine. The above-mentioned valve isopened by the control unit of the dialysis machine only when thetemperature of the cleaning liquid, measured by the above-said sensor,has exceeded a predetermined suitable threshold.

EP 701827 describes a dialysis machine connected to a source of watervia a control valve having two inlet ports, one for the water andanother for the chemical disinfectant, and at least an outlet port whichis connected to the intake of a pump and which is selectively placed incommunication with one or the other of the inlet ports by means of amobile obturator.

U.S. Pat. No. 5,256,371 describes a device for connecting a dialysiscircuit of a dialysis machine to an external liquid source, in which thesource normally comprises a water supply connection and a waterdischarge connection predisposed on the clinic's wall. The connectingdevice comprises an inlet line, an outlet line, a bypass line, and fivevalves arranged on the bypass line, two on the outlet line before andafter the bypass line, and the other two on the inlet line before andafter the bypass line. U.S. Pat. No. 5,256,371 further describes amethod which uses the above-said connecting device for completedisinfection of both the dialysis machine and the above-mentionedconnections fixed to the clinic's wall.

EP 622086 describes a connection of a dialysis machine to an externalliquid source, the connection being provided with a safety devicecomprising two valves arranged in series along the connecting line, apump for pressurising the intermediate tract of line comprised betweenthe two valves, a pressure sensor operating between the two valves, anda control unit which performs a check on the integrity of the valves bymonitoring the pressure in the intermediate tract of line.

SUMMARY OF THE INVENTION

An aim of the present invention is to provide a connecting device whichcan connect, in safe conditions, a medical apparatus to a liquid source.

A further aim of the invention is to realise a medical system in which acentralised source of a liquid can be connected in safe conditions to aplurality of remote medical apparatus.

A further aim is to provide an apparatus for extracorporeal bloodtreatment which can be connected in safe conditions to a centralisedsource of an operating liquid.

An advantage of the invention is to provide a connecting device which isconstructionally simple and economical and considerably reliable, andwhich ensures against the risk of back-contamination on the part of acontaminating agent (for example a disinfectant liquid and/or a cleaningliquid) which, coming from a medical apparatus, can spread to a fluiddistribution system to which the apparatus is connected.

A still further advantage is represented by the fact that the connectingdevice can provide the desired degree of safety by means of a monitoringsystem which uses sensors (for example liquid level sensors orliquid/air presence sensors) of relatively low-cost and highly reliable.

The device of the invention can usefully operate in a system fordistributing an operating liquid to various medical work stations. Thedevice is for protecting the distribution system from contamination by acontaminating liquid in the case of a malfunctioning of one of the workstations using the contaminating liquid (this is the case, for example,of a work station which is performing a chemical disinfectiontreatment).

These aims and others besides are all attained by the present invention,as it is characterised in one or more of the appended claims.

In a specific embodiment of the invention, the connecting device is ableto generate a safety barrier constituted by a volume of air internallyof a buffer chamber.

In a specific embodiment of the invention, the connecting devicecomprises a buffer chamber able to generate a volume of air whichinterrupts a liquid communication between two zones of a liquidtransport line, and a monitoring system of any leaking of liquidentering into the volume of air defined in the buffer chamber. Thismonitoring system can comprise one or more means for detecting thepresence/absence of liquid/air in the above-mentioned buffer chamber.

In a specific embodiment of the invention, the monitoring systemcomprises one or more liquid level sensors (for example a series ofthree or four or even more sensors distributed to operate at variouslevels in the buffer chamber) or other sensor systems for identifyingthe quantity of liquid/air present in the buffer chamber, and/or todetect the presence/absence of liquid/air in the buffer chamber or, atleast, in a predetermined zone of the chamber itself.

Further characteristics and advantages of the present invention willbetter emerge from the detailed description that follows, of at least anembodiment of the invention, illustrated by way of non-limiting examplein the accompanying figures of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The description will be made herein below with reference to theaccompanying figures of the drawings, provided by way of non-limitingexample, in which:

FIG. 1 is an embodiment of a connecting device between a medicalapparatus and a source of a liquid, made according to the presentinvention;

FIG. 2 is a first embodiment of an apparatus for extracorporeal bloodtreatment which uses the connecting device of FIG. 1;

FIG. 3 is a second embodiment of an apparatus for extracorporeal bloodtreatment which uses the connecting device of FIG. 1.

DETAILED DESCRIPTION

With reference to FIG. 1, 1 denotes in its entirety a connecting deviceof a medical treatment apparatus (schematically illustrated and denotedby 11) to a liquid source (schematically illustrated and indicated by4). The connecting device 1 comprises a buffer chamber 2 having at leasta fluid passage section which is greater than the fluid transport lineswhich lead from the chamber itself. The buffer chamber 2 definessubstantially a widening of section along a fluid transport line; at thesection-widening the flow slows down. The buffer chamber 2 is extendedin height in order to define at least an upper part and at least a lowerpart. The buffer chamber 2 is predisposed to generate an air barrierwhich interrupts two consecutive tracts of a fluid transport line. Thebuffer chamber 2 forms an air gap which functions as a safety elementagainst undesired passage of liquid (in one direction and/or in theother) at determined operative stages in which it is necessary toguarantee separation or isolation between the medical apparatus and theliquid source, which source can be used by the medical apparatus inother operative stages for liquid supply. In substance, the bufferchamber 2 serves to ensure than in some predetermined operating stagesin which the passage of liquid is undesired, the passage of liquid iseffectively stopped. The above guarantee is given by verification of thepresence of air, or in any case of a sufficient quantity of air in thebuffer chamber 2 itself during the operating stages which requireseparation or isolation.

The device 1 comprises a first connecting line 3 having a first endwhich is connectable to a liquid source 4 and a second end connected toan inlet 5 arranged in an upper zone of the buffer chamber 2. The firstend of the first connecting line 3 can be connected to the liquid source4 in a fixed connection or, as in the illustrated embodiment, via anyknown type of removable connection 6. A first valve 7 and a second valve8 are arranged in series on the first connecting line 3. The first valve7, as well as the second valve 8, is in the specific case an on-offvalve (for example a solenoid) commanded by a control unit (notillustrated).

The connecting device 1 comprises a second connecting line 9 having afirst end connected to an outlet 10 arranged in a lower zone of thebuffer chamber 2 and a second end connectable to the medical treatmentdevice 11. The second end of the second connecting line 9 can beconnected to the medical treatment device 11 in a fixed way, as in theillustrated embodiment, or via any known type of removable connection.The outlet 10 is arranged at a lower level than the inlet 5. A liquidmoving pump 12 is predisposed on the second connecting line 9 totransport the fluid. The liquid moving pump 12 is of the reversibletype, i.e. it can move the liquid in one direction or another. Theliquid moving pump 12 is, in the specific embodiment, a positivedisplacement pump, for example with a rotary and oscillating piston. Itwould however be possible to use any type of known pump, in particular avolumetric pump or any other type of pump of system for fluid movementalong a line or a circuit for fluid transport. The second connectingline 9 is provided with a bypass line 13 for bypassing the liquid movingpump 12. The bypass line 13 is provided with a bypass valve (for examplean on-off valve) which is commanded by the control unit (the bypassvalve can be, for example, a solenoid).

The connecting device 1 is provided with a liquid/air detector operatingin the buffer chamber 2 between the inlet 5 and the outlet 10. Theliquid/air detector can comprise any sensor or system of sensors able toprovide a signal indicating the presence or not of gas (air) in thebuffer chamber 2 or in any case the presence of a determined quantity ofgas (air) internally of the buffer chamber 2 itself. The liquid/airsensor can comprise, for example, a moisture sensor (the absence ofmoisture, or presence of a quantity of moisture which is below apredetermined threshold being indicative of the presence of air), or apressure sensor for volumetric measuring of gas (the pressure signalbeing processable in such a way as to determine the volume of airpresent in the buffer chamber 2, for example on the basis of theequation of state of an ideal gas and the knowledge of the volume of thebuffer chamber 2, as well as possibly the temperature), or any knowntype of liquid level sensor (of the YES/NO type) or liquid levelmeasuring device (which provides a signal indicating the level), such asfor example a sensor or ultrasound-type level measuring device, or otheracoustic signal, or optical, or mechanical (for example a float-typedevice) or any other type. In the specific embodiment the liquid/airdetector comprises a first and a second liquid level sensor,respectively 15 and 16, for example of the optic type, arranged at twodifferent levels (one above the other) and configured to signal thepresence of liquid in the buffer chamber 2 at a first and, respectivelya second liquid level, both levels being intermediate between the inlet5 level and the outlet 10 level of the buffer chamber 2. As alreadymentioned, the upper level sensor 15 operates at a lower level than theinlet 5 of the buffer chamber 2. The lower level sensor 16 operates at ahigher level than the outlet 10 level of the buffer chamber 2.

The connecting device 1 further comprises a vent line 17 connected to anupper zone of the buffer chamber 2 and provided with a vent valve 18,for example a solenoid or another type of valve activated on command bythe control unit. The vent line 17 is further provided with one or moreair filters 19 (for example hydrophobic membrane filters) forcommunication with the outside environment.

The control unit of the connecting device 1 is connected to theliquid/air detector (i.e., in the specific embodiment, the two levelsensors 15 and 16), to the first valve 7 and second valve 8 of the twofirst connecting lines 3, to the liquid moving pump 12 of the secondconnecting line 9 and to the vent valve 18 on the vent line 17. Thecontrol unit is further connected to the medical treatment device 11 (itcan, for example, be a control unit of the device 11 itself).

The control unit is programmed to perform a safety control procedurewhich comprises the following operations:

a) Receiving data from the outside to recognise whether the medicaltreatment device 11 is in a mode requiring the separation or isolationof the liquid source 4, such as for example a disinfecting mode and/or awashing mode;

b) Closing both the first valve 7 and (if present) the second valve 8when it is recognised that the medical treatment device 11 is in adisinfecting mode and/or a washing mode or in any other mode whichrequires, for example for reasons of safety, the isolation or separationof the medical treatment device 11 from the liquid source 4;

c) Signalling an anomalous situation (the signal can comprise, forexample, one or more from the following operations: an acoustic orvisual signal 9, an on-screen message on the user interface of themedical apparatus 11, an automatic interruption of one or more functionsunderway by the medical apparatus 11, any operating mode known forplacing the medical apparatus 11 in a safe situation etc.) if, while themedical apparatus 11 is in the mode requiring isolation/separation (forexample disinfection/washing), the liquid/air detector of the liquiddetects liquid in the buffer chamber 2 above a predetermined level (orin any case it detects a quantity of liquid above a certain thresholdand/or a quantity of air below a certain threshold).

The above-mentioned safety control procedure can further include thecontrol unit's being programmed to open the vent valve 18 in a case inwhich the medical apparatus 11 is recognised to be in a disinfectingand/or washing mode or in another mode requiring isolation/separation.

The above-described safety control procedure has the function ofensuring that between the medical apparatus 11 and the liquid source 4there is a safety barrier, represented by a volume of air, in thepresent embodiment a buffer chamber 2 full of air. As mentioned, thesafety barrier must be ensured during certain operating stages of themedical apparatus 11 in which the medical apparatus 11 has to beabsolutely separate (that is, not in liquid communication) with respectto the liquid source 4, (in the present embodiment one of the operativestages consists if the procedure of disinfection and/or washing). Thisensures, in particular, that the disinfecting and/or washing liquidcirculating in the medical apparatus 11 does not pass into circulationtowards the liquid source 4. This guarantee is of fundamental importancewhen, for example, the liquid source 4 is in communication with othermedical apparatus: consider a case in which the liquid source 4comprises or is part of a centralised plant distributing a liquid to amultiplicity of remote medical apparatus. In this case the safetycontrol procedure guarantees, for example, that while the medicalapparatus 11 is performing a disinfection and/or washing procedure,there is no risk that the disinfection and/or washing liquid can besupplied, by error, to a patient who is contemporaneously subjected to atreatment by a further medical apparatus which is also connected to thesame centralised distribution plant. In general the above-describedcontrol procedure prevents a dangerous situation in which, in a systemcomprising a centralised distribution plant of a liquid connected to aplurality of medical apparatus by means of a plurality of connectingdevices such as the one described herein above, a second liquid used bya single medical apparatus might diffuse by error internally of thecentralised plant. A typical case of a risky situation is, for example,when a first medical apparatus is performing a first procedure using thefirst liquid coming from the centralised distribution plant (for examplea medical treatment using a medical liquid), while a second medicalapparatus is performing a second procedure, which does not require thefirst liquid and which uses a second, dangerous liquid (for example thedisinfecting and/or washing liquid of the apparatus) which, ifintroduced into the circuit of the first apparatus while performing thefirst procedure, could cause serious harm to the health of the patientand/or a pollution of the entire distribution network of the firstliquid.

The control unit is further programmed to perform a valve integrity testcomprising the following stages:

a) activating the reversible liquid pump 12 to empty the buffer chamber2 of liquid, in which the emptying stage is performed with the firstvalve 7 closed and the vent valve 18 open (the second valve 8, ifpresent, can be closed too, or even left open, as will be explained inmore detail herein below);

b) activating the reversible liquid pump 12 in order to aspirate/pumpfluid from/to the buffer chamber 2 after the first stage a) of emptying,in which the stage of aspiration/pumping is performed with the firstvalve 7 closed and the vent valve 18 also closed (in this stage too thesecond valve 8, if present, can be open or closed);

c) check if, after stage b) of aspiration/pumping, the buffer chamber 2is still empty of liquid, the check being performed by the level sensorsystem 15 and 16.

The above integrity test can be performed, as mentioned, in aspiration(depression of the buffer chamber 2); the liquid moving pump 12 isreversible and therefore can function in both directions. It has beenobserved however that the test performed in compression, where theliquid movement pump 12 is pumping towards the buffer chamber 2, seemsto be more efficient.

The integrity test can be performed, as already mentioned, with thesecond valve 8 open, with the aim of checking the integrity of only thefirst valve 7, and then can be repeated to check the integrity of thesecond valve 8, this time keeping the first valve 7 open. Thisrepetition therefore comprises the following stages:

a) Activating the reversible liquid pump 12 to further aspirate/pumpfrom/to the buffer chamber 2 empty of liquid (full of air), in whichthis stage of further aspiration/pumping is performed with the secondvalve 8 closed, the vent valve 18 closed, and the first valve 7 open;

b) Checking if, after the stage of further aspiration/pumping, thebuffer chamber 2 is still empty of liquid (i.e. substantially full ofair).

In an embodiment of the invention which is not illustrated, more thanone first connecting line 3 could depart from the buffer chamber 2, aswell as and/or more than one second connecting line 9. In other words,the connecting device can comprise: one or more further first connectinglines, each of which has a first end which can be connected to one ormore liquid sources (for example for supplying different liquids) and asecond end connected to an inlet arranged in the upper zone of thebuffer chamber; one or more further first valves (and possibly secondvalves) each of which is arranged in a respective line of theabove-cited further first connecting lines; one or more further secondconnecting lines, each of which has a first end connected to an outletarranged in the lower zone of the buffer chamber and a secondconnectable to one or more medical treatment apparatus; and one or morefurther liquid movement pumps, each of which is arranged in a respectiveline of the further second connecting lines. With this embodiment toothe control unit can be programmed to perform the above-described safetycontrol procedure and the above-cited valve integrity test.

The connecting device of the invention can be applied to a medicalsystem comprising one or more medical apparatus connected to at least aliquid source via one or more of these connecting devices. The liquidsource 4 can comprise, as previously mentioned, a centraliseddistribution plant of an operating liquid, in which the operating liquidcan comprise one or more of the following liquids: a chemicaldisinfectant and/or a washing liquid for the disinfecting/cleaning ofthe fluid transport circuit of the medical apparatus, a hot disinfectant(water or another heated liquid, heated to a disinfecting temperature),a medical treatment fluid (for example a dialysis fluid and/or areplacement fluid for performing a hemodialysis and/orhemo(dia)filtration treatment), a fluid containing one or morecomponents of a treatment fluid (for example a solution—concentrated—ofbicarbonate, or sodium chloride, or a mixture of one or more salts for ahemodialysis or hemo(dia)filtration, such as for example sodium,magnesium, potassium, calcium, glucose, etc.) an infusion fluid etc. Themedical apparatus of the above-described medical system can comprise oneor more extracorporeal blood treatment, such as for example ahemodialysis apparatus, a hemo(dia)filtration apparatus, a hemoperfusionapparatus, a plasmapheresis apparatus, a therapeutic plasma exchange, anapparatus for treatment of hepatic insufficiency, etc.

FIGS. 2 and 3 illustrate two examples of how the connecting device 1 canbe connected to an apparatus for extracorporeal blood treatment. Theelements which are the same in FIGS. 2 and 3 have been denoted using thesame numbers, for the sake of simplicity.

The extracorporeal blood treatment apparatus of FIG. 2 comprises amembrane device 20 for extracorporeal blood treatment which in turncomprises a first chamber 21 and a second chamber 22 separated by asemipermeable membrane 23. The apparatus comprises an extracorporealblood circuit connected to the second chamber 22 (blood chamber) of themembrane device 20. The extracorporeal blood circuit can comprise anyone of the blood circuits of known type which are usable in a dialysisapparatus and/or a hemo(dia)filtration apparatus. The extracorporealblood circuit in FIG. 2 has been schematically represented as anarterial line 24 for blood removal from the patient and in a venous line25 of return of blood to the patient. The apparatus further comprises afluid circuit comprising a fresh treatment fluid supply line 26connected to an inlet of the first chamber 21, and a used treatmentfluid discharge line 27 connected to an outlet of the first chamber 21.The fresh treatment fluid supply line 26 further has an inlet endconnected to a water source 28. The used treatment fluid discharge line27 further has a discharge end connected to a drainage 29. The fluidcircuit is provided with at least a fluid movement pump 30 along thecircuit itself and a first ultrafilter 31 for reducing the quantity ofbacteria and/or endotoxins in the treatment fluid upstream of themembrane device. The apparatus further comprises a fluid balancingsystem 32 for controlling the flow balance in the fresh treatment fluidsupply line 26 and the used treatment fluid discharge line 27 before andafter the membrane device 20. The fluid balancing system 32 can compriseanyone of the known balancing systems used in hemodialysis apparatus(volumetric balancing chamber system, two flow-meter system,differential flow-meter system, scale system etc.). The apparatusfurther comprises at least a connecting device 1 such as the onedescribed above (in the specific case it comprises two, as will beexplained in more detail herein below). The second end of the secondconnecting line of each connecting device 1 is connected to the fluidcircuit. In particular the second end branches, for each device, from arespective branch point 33 of the fresh treatment fluid supply line 26.Each of the branch points 33 is in a zone arranged upstream of the fluidbalancing system 32. In the specific example, in which there are twoconnecting devices 1, both have the second end of the second connectingline which branches from two branch points 33 arranged on the freshtreatment fluid supply line upstream of the fluid balancing system 32.The two connecting devices 1 are inserted in an on-line preparationsystem of a fresh fluid treatment starting from water and concentrates.In particular the preparation system can comprise any one of the knownsystems for on-line preparation of a dialysis fluid starting from waterand concentrates. In the specific case the preparation system comprisesat least two concentrate containers 34 which receive water from thewater source 28 via a branch line 35 which branches from the main supplyline fresh treatment fluid supply line 26. The preparation system caninclude a third concentrate container (not illustrated). The watercoming from the source 28 (possibly heated and degassed) is mixed, in aknown way, with the concentrates contained in the containers 34 to giverise to a concentrated solution which is introduced into the freshtreatment fluid supply line 26 to form, finally, the fresh treatmentfluid to be sent to the first chamber 21 of the membrane device 20and/or the extracorporeal blood circuit. Sensors are included (of knowntype and not illustrated, such as for example electrical conductivitysensors, temperature sensors, pH sensors) to check that the freshtreatment fluid possesses the desired characteristics (in particular thetemperature and chemical composition). The treatment fluid preparationsystem, being substantially of known type, is not described in furtherdetail. Of importance is the fact that the connecting devices 1 enableselective connection with the concentrate containers 34 or with twosources of concentrate solution 36 which are part of a centraliseddistribution system. The selective connection can be performed manuallyby means of the connections 6 and the corresponding removablecounter-connections 6′ and 6″, which both the concentrate linesconnected to the concentrate containers 34 and the concentrate linesconnected to the sources 36 which are part of the centralised systemdistribution are equipped with. The connecting devices 1 ensure thateven in a case where the counter-connections 6″ of the concentratesolution 36 sources belonging to the centralised distribution system arenot removed but remain coupled to the removable connections 6 of theconnecting devices, there is no risk of the polluting fluid's passingfrom the extracorporeal blood apparatus to the centralised distributionsystem (and vice versa).

In the specific case of FIG. 2, the extracorporeal blood treatmentapparatus is a hemodiafiltration apparatus comprising a replacementfluid supply line 37 provided with a second ultrafilter 38. In thespecific case of FIG. 2 a hemodiafiltration apparatus in post-dilutionis illustrated, although it would be possible with the apparatus inpre-dilution, or in pre- and post-dilution. The application can also beused in a hemodialysis apparatus, or in a hemofiltration apparatus, inwhich case the connecting device or devices can be connected to thereplacement fluid supply line 37. It is also possible, in ahemodiafiltration apparatus, for one or more connecting devices 1 to beconnected to the dialysis fluid supply line (as in FIG. 2) and/or thereplacement fluid supply line.

With reference to the hemodialysis apparatus of FIG. 3, the sameelements that appeared in FIG. 2 have been denoted using the samenumbers, and will not be further described. The fresh treatment fluidsupply line 26 is provided with a device for on-line preparation of thefluid 39 starting from water and concentrates. The preparation device 39can be any known device used in a machine for hemodialysis and/orhemo(dia)filtration, or the preparation device described with referenceto FIG. 2 and provided with one or more connecting devices 1. The freshtreatment fluid supply line 26 has an inlet end which is provided withthe connecting device 1. The fresh treatment fluid supply line 26further has an ultrafilter 40 for reducing the quantity of bacteriaand/or endotoxins in the flow arranged between the connecting device 1and the on-line preparation device 39. The first end of the firstconnecting line 3 of the connecting device 1 is destined, in thespecific case, to connection with a source of purified water 41 suppliedby a centralised plant for production and distribution of purified waterto a multiplicity of remote medical apparatus. The source of purifiedwater 41 can comprise, for example, an inverse osmosis system. Thesource of purified water 41 is provided with an end for connecting tothe connecting device 1 by means of a counter-connector 6′ removablyconnectable with a corresponding connector 6 which the first end of thefirst connecting line 3 is provided. The connecting device 1 can beconnectable (selectively) with a further source of liquid 42 providedwith a corresponding counter-connector 6″. The further source of liquid42 can comprise, for example, a supply of a disinfecting fluid, athermal and/or chemical liquid, which can originate from a centralisedfluid production and distribution plant. The further source of liquid 42can comprise, in a further example, a supply of a treatment fluid (forexample a dialysis and/or a replacement fluid) which can operate incooperation or alternatively to the preparation device 39 and which canbe sourced from a centralised fluid production and distribution plant.In each case, the connecting device 1 provides a guarantee against riskof back-contamination of the sources 41 and 42 or of the extracorporealblood treatment apparatus, in determined operative stages of the sources41 and 42 or the extracorporeal blood treatment apparatus, where thelatter must be isolated from the sources 41 and 42. The hemodialysisapparatus of FIG. 3 can be provided with a pre-dilution line and/or apost-dilution line in order for a hemo(dia)filtration treatment to beperformed.

Also in the case of FIG. 2 and line 3, the functioning of the connectingdevice 1 is how it is described with reference to FIG. 1. The liquidmovement pump 12 is activated to supply the medical apparatus withoperating liquid in the operating modes which include use of the liquid(for example in patient treatment mode when the operating liquid is atreatment liquid), with the first valve 7 and the second valve 8 open;in this situation at least the lower level sensor 16 will detect liquid.When a mode not requiring the treatment liquid is selected or intervenesautomatically, but instead demands isolation of the medical apparatusfrom the operating liquid source (for example a disinfecting mode), thefirst valve 7 and the second valve 8 will be closed and the liquidmovement pump 12 will be activated to empty the buffer chamber 2 (withthe vent valve 18 open) until the two level sensors 15 and 16 bothdetect air. In this situation, between the medical apparatus and thecentralised system of distribution an air spacer is interposed, whichfunctions as a safety barrier. The valve integrity test comprisesclosure of a valve on the first connecting line 3 (for example the firstvalve 7) and the closure of the vent valve 18 (keeping the second valve8 open, even if, as has been observed, it can be closed to perform acontemporary integrity test on both valves) and the activating of theliquid moving pump 12 in inverse direction for pumping towards thebuffer chamber 2 (as has been observed, a test under aspirationconditions is also possible): if the first valve 7 and the vent valve 18are in the correct sealedly closed position, the upper level sensor 15and lower level sensor 16 should in all cases detect the presence ofair. The valve integrity test is repeated for the second valve 8 whichis closed, while the first valve 7 is opened and the vent valve 18 iskept closed; the pumping action towards (or aspiration from) the bufferchamber 2 is repeated and the integrity test is considered to have beenconcluded with success if this time too the upper and lower levelsensors 16 both detect air.

The connecting device 1 associated to the apparatus of FIGS. 2 and 3 cancomprise any one of the connecting devices 1 described in the claimsthat follow relative to a connecting device. The functioning of thedevices is the same and directly deducible from what is stated withreference to the functioning of the device of FIG. 1.

Legend 1 Connecting device of a medical treatment apparatus to a sourceof a liquid 2 buffer chamber 3 first connecting line 4 liquid source 5buffer chamber inlet 6 6′ 6″ removable connections 7 first valve 8second valve 9 second connecting line 10 buffer chamber outlet 11medical treatment apparatus 12 reversible liquid pump 13 bypass line 14bypass valve 15 first liquid level sensor 16 second liquid level sensor17 vent line 18 vent valve 19 air filter 20 membrane device forextracorporeal blood treatment 21 first chamber of membrane device 22second chamber of membrane device 23 semipermeable membrane 24 arterialline 25 venous line 26 fresh treatment fluid supply line 27 usedtreatment fluid discharge line 28 water source 29 drainage 30 fluidmoving pump 31 ultrafilter pump 32 fluid balancing system 33 branchpoint 34 concentrate containers 35 branch line 36 concentrate solutionsources 37 replacement fluid supply line 38 second ultrafilter 39 devicefor on-line preparation of an operating fluid starting from water andconcentrates 40 ultrafilter 41 purified water source 42 further liquidsource

1-23. (canceled)
 24. A connecting device of a medical apparatus to a liquid source, comprising: a buffer chamber having an upper zone, a lower zone, an inlet arranged in the upper zone, and an outlet arranged in the lower zone; a first connecting line having a first end which is connectable to the liquid source and a second end connected to said inlet; a second connecting line having a first end connected to said outlet and a second end connectable to the medical apparatus; a first valve arranged in the first connecting line; a pump arranged in the second connecting line; at least a liquid/air detector operating in the buffer chamber.
 25. The device of claim 24, wherein the liquid/air detector operates at least between the inlet and the outlet.
 26. The device of claim 24, wherein the liquid/air detector comprises a first level sensor which is configured to signal presence of liquid/air in the buffer chamber and at least a first intermediate level between said inlet and said outlet.
 27. The device of claim 26, wherein the liquid/air detector comprises a second level sensor configured to signal presence of liquid/air in the buffer chamber at a second intermediate level between said inlet and said outlet, the second level being different from the first level.
 28. The device of claim 24, wherein the liquid/air detector comprises one or more sensors selected from a group of sensors which includes: a moisture sensor, a pressure sensor for volumetric measurement of gas, a level sensor or level measure of acoustic type, an ultrasound liquid level sensor, a level sensor or level measure of optic type, a level sensor or level measure of mechanical type, a float liquid level sensor, a combination of the said sensors.
 29. The device of claim 24, comprising a second valve arranged in series with the first valve along the first connecting line.
 30. The device of claim 24, comprising a vent valve connected to the buffer chamber.
 31. The device of claim 24, comprising a control unit connected to the liquid/air detector, to the first valve and to the pump, the control unit being connectable to the medical apparatus and being programmed to perform following operations: receiving data for recognising whether the medical apparatus is in a predetermined operating mode; closing the first valve if the medical apparatus is found to be in the predetermined operating mode; signalling an anomalous situation if, while the medical apparatus is in the predetermined operating mode, the liquid/air detector finds liquid in the buffer chamber above a predetermined level.
 32. The device of claim 31, wherein the buffer chamber is connected to a vent valve which in turn is connected to the control unit, and wherein the control unit is programmed to open the vent valve if the medical apparatus is found to be in the predetermined operating mode.
 33. The device of claim 24, comprising: a vent valve connected to the buffer chamber; a control unit connected to the liquid/air detector, to the first valve, to the pump, and to the vent valve; the control unit being programmed to perform, a valve integrity test comprising activating the pump to empty the buffer chamber of liquid, the emptying stage being performed with the first valve closed and the vent valve open; activating the pump to aspirate/pump fluid from/to the buffer chamber after the emptying stage, the aspiration/pumping stage being performed with the first valve closed and the vent valve closed; checking whether, after the aspiration/pumping stage, the buffer chamber is still empty of liquid.
 34. The device of claim 33, comprising a second valve arranged in series with the first valve along the first connecting line; the stage of aspiration/pumping being performed with the second valve open; the valve integrity test further comprising stages of: activating the pump to further aspirate/pump fluid from/to the buffer chamber empty of liquid, the further aspiration/pumping stage being performed with the second valve closed, the vent valve closed and the first valve open; checking whether, after the further aspiration/pumping stage, the buffer chamber is still empty of liquid.
 35. The device of claim 24, comprising: one or more further first connecting lines, each of which has a first end which is connectable to a liquid source and a second end connected to an inlet positioned in an upper zone of the buffer chamber; one or more further first valves, each of which is arranged in a respective one of the further first connecting lines.
 36. The device of claim 24, comprising: one or more further second connecting lines, each of which has a first end connected to an outlet arranged in a lower zone of the buffer chamber and a second end which is connectable to the medical treatment apparatus; one or more further pumps, each of which is arranged in a respective one of the further second connection lines.
 37. A medical system comprising: at least a medical apparatus; at least a liquid source; at least a connecting device made according to claim 24 and configured for connecting the medical apparatus with the liquid source.
 38. The medical system of claim 37, wherein the liquid source comprises a centralised distribution plant of an operating liquid to a plurality of medical apparatus.
 39. The medical system of claim 38, wherein the operating liquid comprises one or more liquids selected from a group of liquids which includes: a chemical disinfectant, a cleaning liquid, a thermal disinfectant, a medical treatment fluid, a fluid for hemodialysis or hemo(dia)filtration, a fluid containing one or more components of a fluid for hemodialysis or hemo(dia)filtration, an infusion fluid, purified water, a inverse-osmosis-treated fluid.
 40. The medical system of claim 37, wherein the medical apparatus comprises one or more medical apparatus selected from a group which includes: an extracorporeal blood treatment apparatus, a hemodialysis apparatus, a hemo(dia)filtration apparatus, a hemoperfusion apparatus, a plasmapheresis apparatus, a therapeutic plasma exchange apparatus, a renal insufficiency treatment apparatus.
 41. An apparatus for extracorporeal blood treatment comprising: a membrane device for extracorporeal blood treatment, comprising a first chamber and a second chamber, separated from one another by a semipermeable membrane; a fluid circuit comprising a fresh treatment fluid line connected to an inlet of the first chamber, and a used treatment fluid line connected to an outlet of the first chamber; at least a fluid movement pump along the fluid circuit; a fluid balancing system for controlling the balance of flows in the fresh and used fluid treatment lines; at least a connecting device of claim 24, the second end of the second connecting line of the connecting device being connected to the fluid circuit.
 42. The apparatus of claim 41, wherein the second end of the second connecting line of the connecting device is connected in a branch relationship with the fresh treatment fluid line.
 43. The apparatus of claim 41, wherein the second end of the second connecting line of the connecting device is connected to a branch point of the fluid circuit arranged upstream of the fluid balancing system.
 44. The apparatus of claim 41, comprising one or more further connecting devices, each comprising: a buffer chamber having an upper zone, a lower zone, an inlet arranged in the upper zone, and an outlet arranged in the lower zone; a first connecting line having a first end which is connectable to the liquid source and a second end connected to said inlet; a second connecting line having a first end connected to said outlet and a second end connectable to the medical apparatus; a first valve arranged in the first connecting line; a pump arranged in the second connecting line; and at least a liquid/air detector operating in the buffer chamber, the second end of the second connecting line of each of the further connecting devices being connected to the fluid circuit.
 45. The apparatus of claim 44, wherein the second end of the second connecting line of each of the further connecting devices is connected to a branch point of the fresh treatment fluid line positioned upstream of the fluid balancing system.
 46. The apparatus of claim 41, configured to perform one or more of following treatments: hemodialysis, hemofiltration, hemodiafiltration, hemoperfusion, plasma exchange therapy, plasmapheresis, hepatic insufficiency treatment. 